Sintering furnace



Feb. I27 1951 G. c. BURGESS SINTERING FURNACE 4 Sheets-Sheet l FiledOct. 9, 194'? m c QAM e mf/2 6 Feb. 27, 1951 G. c. BURGESS SINTERINGFURNACE 4 Sheets-Sheet 2 Filed Oct. 9, 1947 ma `,i M Y,

Febo 27, 1951 G. c. BURGESS 2,543,150

SINTERING FURNACE Filed Oct. 9', 194'? 4 Sheets-Sheet 4 65.9017@ CBul/aen- Patented Feb. 2?, QS.

UNITED STATES PATENT OFFICE SINTERING FURNACE George C. Burgess,Columbia, Tenn.

Application October 9, 1947, Serial No. 778,879

2 Claims. (Cl, 26S-21) This invention relates to a sintering furnace andhas for its object the provision of a furnace of the characterdesignated which shall be adapted to operate continuously, receiving asintering charge of mixed fuel and material to be sintered, such as ore,and discharge the sintered material therefrom, which furnace shall be oflarge capacity, reliable in operation, and one which will not becomeoverheated in operation.

A further object of my invention is to provide a continuously operatingsintering furnace which shall include improved means to control theignition and burning of the fuel in the sinteringcharge.

A still further object of my invention is to provide a continuouslyoperating sintering furnace which shall embody a rotary drum having agas permeable surface, with a stationary suction chamber disposed withinthe drum and with improved means to seal off the suction chamber fromthe greater portion of the drum and thus confine the feedingandsintering of the charge to a limited area of the drum.

Another object of my invention is to provide a continuous sinteringfurnace embodying a rotary drum with means to feed a sintering charge ofore and fuel onto the surface of the drum, means to control the rate offeed to maintain an even thickness of charge, and means to control therate of combustion of the fuel in the charge thereby to preventoverheating of the furnace.

Apparatus embodying features of my invention is illustrated in theaccompanying drawings forming a partof this application, in which:

Fig. 1 is an end elevational view;`

Fig. 2 is a plan view with parts broken away;

Fig. 3 is a sectional view taken generally along theI line IIL-III ofFig. 1; v

Fig. 4 is a sectional view, partly diagrammatic, taken generally alongthe line IV-IV of Fig. 3; and

Fig. 5 is a diagrammatic sectional View showing the means forcontrolling the rate of combustion on the drum.

Referring to the drawings for a better understanding o'f my invention,my improved apparatus embodies a foundation, or base plate, I Il havingend supporting cradles II and I2 erected thereon, each having asemicircular seat I3 therein, as shown in Fig. l. Supported by thecradles in a manner to be described later isv my improved furnace whichembodies a rotary drum indicated generally by the numeral I4. The drumis made up of end rings I6 and I1 joined together by a plurality oflongitudinally extending bars I8.

Supported by the bars I8 are a series of grates I9 which form agaspermeable surface for the drum to support the sintering charge of mixedfuel and ore thereon. Mounted on the end rings I6 and I1 are a series ofextension rings 2I and 22 which extend entirely around the drum, asshown in Fig. 3, to provide lateral support for the sintering charge.The end rings I6 and I1 are provided with inwardly directed flanges 23and 24 having grooves 26 and 21 therein in which are mounted sealingrings 28 and 29. Each of the rings 28 and 29 comprises outer rings 28aand 29a formed preferably of graphite, and inner rings 28h and 29hformed of steel or cast iron. Extending longitudinally of` the drum, andjoining the inwardly directed flanges 23 and 24 are a series of sealingstrips 3|.

Mounted on the ends of the drum and secured i to the rings i6 and I1 area plurality of brackets 32 and 33 for supporting riding rings 34 and 36,which latter are secured to the brackets. Mounted in the seats I3 of thecradles II and I2 are roller bearings 31 and 36 on which the ridingrings 34 and 36 bear. The rollers of the bearings are retained byspacing rings 39 and 4I at each end of the drum. Also secured to thebrackets 32 and 33 inwardly of the riding rings 34 and 35, are ringgears 42 and 43 each having its gear teeth on the inner surface thereof.vAt 44 I show a driving motor which drives a shaft 46 by means-ofsuitable sprockets and a sprocket chain 41. The shaft 46 extendsentirely through the drum I4 and has mounted thereon pinions 48 and 49which mesh with the ring kgears' 42 and 43 to drive the drum.

Mounted within the drum I4 is a stationary suction chamber comprised ofend walls 5I and 52 and side walls 53 and 54. The side walls 53 and 54,as shown in Fig. 5 of the drawing, extend below the center of the drumI4 to form a trough 56. The trough 56 terminates in flanged openings 51and 58, extending through the end walls 5I and 52, to which areconnectedsuction conduits 59 and 6I Mounted within the trough 56 is ascrew conveyor having ribbon flights I62 .and 63 mounted on a shaft 64.As shown in Fig. 3, the flights 62 and 63 are turned in oppositedirections so that any solid matter passing through the grates I9 willbe delivered out at the ends through the suction openings 59 and 6I. Theshaft 64 is driven from the shaft 46 as shown in Fig. 2 of the drawingas by means of the belt 66 and pulleys 61 and 68.

As shown in Fig. 3, the end Walls 5I and 52 are provided with inwardlyturned flanges 69 and 1I which are concentric with the inwardly directedflanges 28 and 24 of the end rings I 8 and I1 and cooperate with thesealing rings 28 and 28 to prevent the flow of air into the suctionchamber through the ends of the drum. Also, as shown in Fig. 4 of thedrawing. the side walls 58 and 54 of the suction chamber are provided atthe top with skirts 12 and 13 which are concentric with the drum andwhich are of such length as to span the arc between a pair of sealingstrips 8|. Thus. one sealing strip always is cooperating with each ofthe skirts 12 and 18 to intercept the ow of air into the suction chamberaround the side walls thereof.

At the ends oi' the suction conduits 59 and 8|, respectively, aredisposed cyclone separators 14 and '18 for separating from the gases ofcombustion any dust or solid material passing through the grate I9 intothe suction chamber. Each of the cyclone separators is provided with ahinged weighted trap door 11, as shown in Fig. l, to discharge solidmaterial therefrom when suilicient accumulates to open the trap door.

Connected to the cyclones 14 and 16 are suction conduits 18 and 19 whichare in turn connected at their other ends to a single conduit 8| leadingto a motor driven exhaust blower 82. f

The suction chamber, suction conduits, and cyclone separators, aresupported by means of end supports 83 and 84 extending downwardly to thebase or foundation plate I0.

The sintering charge, which, as is well understood, consists of amixture of fuel and material to be sintered, is fed on the drum througha feed chute 86. the rateof feed being controlled as by a motor drivenrotary feeder 81. As the charge falls on the drum, it is leveled oif bymeans of a leveling bar 88 extending across the chute 86 immediatelyabove the drum. The charge is ignited by means of downwardly directedgas jets 89 and combustion is maintained by the air being drawn throughthe charge and the grate I9 by the blower 82.

The electric motor 9| for the feeder 81 is controlled by a switch 92which is biased toward closed position by means of a-spring 93 and whichmay be opened by a solenoid 94 controlled by a circuit 96. One wire ofthe circuit 95 leads to a contact member 91 which is disposed to engagethe top of the charge on the drum and the other wire leads to a contact98 disposed to make sliding contact with the side of the ring 2| or 22.Thus when the charge onthe drum illls up to such an extent that thecontact 91 engages in the charge, the circuit 98 is closed, the solenoid94 is energized and the switch 92 is opened to stop the motor 9|, andthus stops the operation of the feeder '81 to supply charge to the drum.When the charge on the drum falls below the contact 91, the circuit 98is then opened, the solenoid 94 is deenergized and the switch 92 isclosed by the spring 93 to energize the motor 9|.

In order to maintain an even rate of combustion of the fuel in thecharge and particularly to control the rate of combustion during theinitial portion of the travel of the charge on the drum I4, I provide abaille I0| within the suction chamber which is pivoted at its upper end,as shown at |02. The lower free end of the baille is disposed to movetoward the wall 54 by gravity. Connected to the lower end of the bafiieIIII on the opposite side from the wall 54, is a cable |03 leading to adrum |04, driven by a motor |06 through a suitable gear reduction |01.As shown in the drawing, the motor |08 is a reversing motor and-properly sintered, product.

in a manner which will be readily understood from the drawing. Locatedwithin the suction chamber between the wall 58 and the baille IOI is acapsule |09 containing a uid expansibly responsive to a rise oftemperature within the suction chamber. A tube III leads from thecapsule |09 to a, pressure responsive device, such as expansible bellowsII2, connected by means of a rod II3 to the switch |08. Should thetemperature within the suction chamber become too high, pressure withinthe capsule |09 will operate the bellows II2 to close the switch |08 andoperate the motor |08 in a direction to swing the baille IOI with itslower end toward the side wall 53 of the suction chamber, therebyrestricting the downward flow of air through the charge during theinitial portion of the travel of the charge on the drum. Should thetemperature within the suction chamber, between the baille |0I and thewall 53, fall below a predetermined minimum, the fluid within thecapsule |09 contracts, causing the bellows I I2 to contract and operatethe switch |98 to close and cause the motor to run in the oppositedirection, whereupon gravity will cause the baiiie IOI to move towardthe sidewall 54 and thus provide for a larger volume of air to flowthrough the charge. It is contemplated by my invention that the majorportion of the fuel in the charge will be burned between the point whereit is charged on the drum and the upper edge of the baille I 0I where itis pivoted at |02. If the charge contains a minimum of moisture, thefuel in it might burn too fast and overheat the grate I8. If the chargecontains an excess of moisture, the fuel in the charge would not burnfast enough to bring about the desired sintering. By controlling therate of air for combustion through the charge in its travel between thepoint of feed and the upper edge of the baiile IOI, I am enabled tocontrol the rate of sintering and provide for a uniform,

It is also contemplated by my invention, that the motor |05 shall be sogeared down as to operate the baille I0| quite Islowly and that thetemperature response within the suction chamber between the wall 53 andthe baille IIJI will be such that the motor |06 will be stopped byopening of the switch |08 before undesired overtravel is reached ineither direction. It will be obvious. however, that limit switches maybe employed if desired.

After the charge has passed beyond the upper edge of the side wall 54 ofthe suction chamber and is on its downward movement on the drum I4, itis engaged by a scraper I I4 and is removed from the drum.

From the foregoing, it will be apparent that I have devised an improvedsintering furnace which is continuous and automatic in its operation. isof large capacity, and is one in which the combustion is so controlledthat there is no danger of the parts becoming overheated. It willfurther be seen that I have devised an improved means to control boththe rate of feed and the rate of combustion in the furnace.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications, without departing from the spiritthereof, and I desire therefore, that only such limitations shall beplaced thereupon as are specifically set forth in the appended claims.

What I claim is:

1. A sintering furnace comprising a hollow iS Controlled by means of areversing switch |08 16 rotary drum having a gas permeable surface.

means defining a stationary suction chamber within the drum, saidchamber having an open top subtending an arc within the upper quadrantof the drum, means to feed a sinterlng charge of ore and fuel onto thesurface of the drum to be carried thereby over the suction chamber,means to ignite the fuel in the charge at the beginning of its travel onthe drum, suction means connected to the bottom of both endsof thesuction chamber to draw air for combustion through the charge, a movablebae extending longitudinally within the suction chamber intermediate itssides for varying the suction through the charge during the initialportion of its travel, a motor operatively connected to the baille forvarying its position,

` and temperature responsive means within the chamber for controllingthe motor.

2. A sintering furnace comprising a rotary drum having a gas permeablesurface for supporting a sintering charge, a stationary suction chambermounted within the drum and having an open top subtending an arc in theupper quadrant of the drum and having side and end walls cooperatingwith the surface and ends of the drum to seal off the remainder of thesurface of the drum, suction conduits connected to the bottom of bothends of the suction chamber, a baille extending longitudinally withinthe chamber intermediate the sides thereof and suspended from its upperedge therein, a motor operatively connected to the lower portion of thebale to vary its position in the chamber, and means responsive totemperature within the chamber for controlling the motor.

. GEORGE C. BURGESS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 916,394 Dwight et al. Mar. 23,1909 1,401,054 Delacourt Dec. 20, 1921 1,471,402 Lloyd Oct. 23, 19231,489,938 Hale Apr. 8, 1924 1,880,146 Morison Sept. 27, 1932 1,961,893Wadman et al June 5, 1934 1,992,704 Lellep Feb. 26, 1935 2,064,495Queneau Dec. 15, 1936 2,123,593 Vogel-Jorgensen July 12, 1938 2,187,727Brown Jan. 23, 1940 2,193,698 Rolfsen Mar. 12, 1940 2,244,372 PomeroyJune 3, 1941 2,283,053 Gohre May 12, 1942 2,410,944 Johnson. Nov. 12,1946

